“This is a battle for Colorado’s soul,” says John Caldara, president of the libertarian Independence Institute and a supporter of the recalls. “Do we maintain the greatness of Colorado, or are we on a certain fast track to becoming California? ... It comes down to a question of who controls policy in Colorado, Michael Bloomberg or the state of Colorado and its representatives?”

Supporters of the two embattled state senators, John Morse, the president of the Colorado Senate, and Angela Giron, also agree about the election’s importance, but for different reasons.

If the recalls succeed, they say, that could set a dangerous precedent in which recall powers are abused to try to remove any elected official who casts a controversial vote.

“This is beyond the bounds of the normal use of recall,” says Craig Hughes, a Democratic political consultant based in Denver. There’s been “a great deal of effort put forward to try to knock out these two senators,” he adds. “Failing it would send the message that this isn’t the way to go.”

The seeds of the recall were planted last winter, when Colorado legislators enacted a package of gun-control reforms, including requiring background checks on private gun sales and limiting ammunition magazines to 15 rounds. At the time, gun-rights advocates warned that they’d go after any vulnerable legislators who supported the bill. Now, six months later, two Democratic senators are fighting for their political lives.

In the absence of federal action on gun control, the Colorado legislation drew national attention. Gun-control measures were being enacted in a Western state in which gun ownership is common but was also the site of two of the worst mass shootings in recent years, at the Aurora movie theater in 2012 and Columbine High School in 1999.

Now, the same interested parties who were involved when Colorado's gun-control legislation was first enacted are watching closely to see the results of the recall votes. Gun-control advocates worry that a successful recall could deter legislators in divided districts from voting on similar issues in the future.

The national implications for gun control are a big reason for the amount of money involved; the two sides have already spent about $2 million. Campaign finance reports last week revealed that Mayor Bloomberg had given $350,000 to defeat the recalls, and Mr. Broad, a top supporter of Bloomberg’s Mayors Against Illegal Guns, had donated $250,000. On the other side, the NRA has given more than $350,000. And the Koch brothers have been involved through their Americans for Prosperity group, which hasn’t had to disclose how much it has spent because it’s technically just “educating” voters about the senators’ positions.

Recall proponents, not surprisingly, are stressing the outside influence. One ad, paid for by Rocky Mountain Gun Owners, accuses Senator Morse of taking his “marching orders” from “East Coast liberals like billionaire playboy New York City Mayor Michael Bloomberg.” “Bloomberg, who has tried to ban guns, salt, and Big Gulps in New York, is bringing his radical agenda to Colorado Springs,” says the ad.

“The recalls show that Senators Morse and Giron have gone too far with their anti-gun agenda,” says Dudley Brown, executive director of Rocky Mountain Gun Owners, in an e-mail.

Morse and Giron have sought a cease-and-desist order against another ad, by Free Colorado, which takes a quote from Morse out of context and accuses Morse (a gun owner himself) of saying that gun owners are “a sickness on our souls.” The same ad claims that Giron paid “political thugs to harass recall supporters” – an allegation her supporters say is "preposterous" and unsubstantiated by facts.

But observers say the recall efforts have also tapped into a discontent among conservative and rural Coloradans that goes beyond just the gun-control measures. Many see the state increasingly controlled by urban – and generally liberal – interests, at the expense of the state’s rural roots.

Legislation enacted last year by the Democratic-controlled House and Senate included a number of controversial bills beyond gun control, including measures that legalized civil unions for same-sex couples, mandated new green-energy requirements for rural electric cooperatives, allowed for same-day voter registration, and allowed undocumented immigrants to pay in-state tuition.

In the northeast part of Colorado, several counties are now proposing secession to form a 51st state – not a proposal that has any serious chance of taking place, but one that crystallizes the disconnect some counties now feel from state government.

“The bigger narrative that flows from this recall is that the Democrats, and particularly this governor who is up for reelection, is on the defensive,” says Floyd Ciruli, a Colorado pollster and political analyst. “At the moment there is a sort of thermador going on, a reversal” from the political climate that gave Democrats control of both the statehouse and the governor’s office.

“The gun safety votes were the trigger for the recall, and I think since then it’s moved beyond that,” says Mr. Hughes. “Anyone who has a grudge about any vote is trying to settle it with these elections.… A lot of people on the Republican side used to having certain levels of power are now on the outside, and we’re seeing some pretty dramatic attempts to reclaim that power.”

Both sides are currently engaged in an all-out battle in the two districts, around Colorado Springs and Pueblo, both in the southern part of the state – barraging voters with advertisements, going door-to-door to drum up support, and doing anything they can to get out the vote next Tuesday.

Turnout is likely to decide the elections. Recall proponents won an important victory when they got the state to require voting to be done in-person – an anomaly in a state where more than 70 percent of voters usually cast their ballots by mail. On the other hand, opponents of the recall have more money, and incumbents often have the advantage.

A recent poll by Quinnipiac University found that Colorado voters oppose the recall efforts and, by a 2-to-1 margin, say that when people don't agree with a legislator, they should wait for reelection, rather than try a recall. Asked specifically about Morse and Giron, voters in the poll opposed their recall by margins of 19 points and 16 points, respectively. This despite the fact that a majority of voters in the same poll opposed the new Colorado gun-control laws.

That poll, however, was of the whole state – and its anybody’s guess just who will turn out on Tuesday.

“The Democrats have incumbents and money working for them, but the narrative has helped Republicans,” says Mr. Ciruli, noting that in each district, recall proponents got more than 10,000 signatures for their recall petitions. “This is all about turnout.”